Complexes of some lanthanide picrates (Ln 3+ = Pr 3+, Nd 3+ and Dy 3+ ) with 15-crown-5 and 18-crown-6 were synthesized and characterized by elemental analysis, ICP-AES, FTIR, 1 H-NMR, 13C-NMR and UV-Visible spectrophotometric methods, thermal analysis (TGA & DTG), magnetic susceptibility , molar conductance and melting points. Also an in-vitro study on pathogenic gram positive (Staphylococcus aureus) and pathogenic gram negative bacteria (Escherichia coli, Salmonella and pseudomonas aeruginosa) was performed and the results were compared to those of a broad spectrum antibiotic (Chloramphinicol). 3+ and Dy 3+ were coordinated with two 15-crown-5 ligands and one picrate anion through its phenolic oxygen and the oxygen of it's ortho nitro group, except for Pr 3+ which was coordinated with only one 15-crown-5 ligand leaving three picrate anions as counter ions. In 18-crown-6 complexes both Pr 3+ and Nd 3+ were coordinated with one 18-crown-6 ligand leaving all the three picrate anions as counter ions outside the coordination sphere, except for the Dy 3+ complex which was coordinated with one 18-crown-6 ligand and one picrate anion.